Antidepressant found to cause growth of new neurons in adult brains

The production of new neurons, known as neurogenesis, was found to be induced in the adult normal cortex by the antidepressant fluoxetine, as reported in a study published online last week in Neuropsychopharmacology.

The research team, based in Japan at the Institute for Comprehensive Medical Science, Fujita Health University, Aichi, had already demonstrated that neural progenitor cells exist at the surface of the adult cortex, and that ischaemia - an insufficient blood flow to the brain which leads to cell death, and is for example the brain-damaging symptom of strokes - apparently enhances the generation of new inhibitory neurons from these neural progenitor cells.

These cells were accordingly named "Layer 1 Inhibitory Neuron Progenitor cells" (L1-INP). But until now it was not known whether L1-INP-related neurogenesis could be induced in a healthy, normal adult cortex.

Tsuyoshi Miyakawa, Koji Ohira, and their colleagues employed fluoxetine, a selective serotonin reuptake inhibitor, and incidentally one of the most widely used antidepressants, to stimulate the production of new neurons from L1-INP cells and had success with this psychopharmacological substance.

A large percentage of the resulting newly generated neurons were inhibitory GABAergic interneurons, and their generation also coincided with a reduction in apoptotic cell death following ischaemia.

This finding highlights the potential neuroprotective response induced by this antidepressant drug. It also lends further support to the thesis that induction of adult neurogenesis in cortex is a relevant prevention/treatment option for neurodegenerative diseases and psychiatric disorders.